'function' Object Has No Attribute 'value' When Class Function Is Used In Enum Values

I just want to achieve some extra which is not there in operator module of python like not_contain. For that I created my own class with the not_contain method. I just want to do s

Solution 1:

Enum uses the presence of the __dunder__ method __get__ to determine if an object is a function/class. Functions and classes created in Python all have a __get__ method, but built-in functions do not.

To get around this problem you can use the aenum module and its member function:

from aenum import Enum, member
importoperatorclassUserDefinedOperators:
    #@staticmethod
    def not_contain(self, a, b):
            return a not in b


classMyOperators(Enum):
    LT = operator.lt
    GT = operator.gt
    NOT_CONTAIN = member(UserDefinedOperators.not_contain)

and in use

>>> list(MyOperators)
[
  <MyOperators.LT: <built-in function lt>>,
  <MyOperators.GT: <built-in function gt>>,
  <MyOperators.NOT_CONTAIN: <function UserDefinedOperators.not_contain at 0x7f9c875ed790>>,
  ]

Note that I made not_contain be a staticmethod. This is appropriate since the not_contain method does not require any instance nor class data to do its job. This also means you do not need to instantiate UserDefinedOperators with creating the NOT_CONTAIN enum member.

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Disclosure: I am the author of the Python stdlib Enum, the enum34 backport, and the Advanced Enumeration (aenum) library.